This International Standard specifies the reference method for the determination of the fat content of milk-based infant foods. The method is applicable to liquid, concentrated and dried milk-based infant foods with no, or not more than a mass fraction of 5 % (dry matter) of such added matter as starch, dextrin, vegetables, fruit, and meat. NOTE 1 Malto-dextrins without higher molecular mass dextrins, which are often present in infant foods, do not disturb the Röse-Gottlieb extraction even when present in high concentrations. The method is not applicable to products which do not dissolve completely in ammonia owing to the presence of starch or dextrin at mass fractions of more than a few percent, or to the presence of hard lumps. The method is also not applicable to products which contain free fatty acids in significant quantities. The results obtained for these products are too low. NOTE 2 For such products, a method utilizing the Weibull-Berntrop principle is suitable (see ISO 8262-1IDF 124-1[3]).